This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A309866 #14 Aug 21 2019 10:57:40 %S A309866 1,2,2,1,0,2,1,0,0,1,0,1,2,0,1,0,2,0,2,1,1,2,1,2,2,1,2,2,1,0,1,1,2,0, %T A309866 2,0,2,1,2,1,2,2,0,0,2,1,1,2,0,2,1,1,0,2,0,0,2,0,1,0,2,2,2,0,1,2,2,0, %U A309866 0,2,0,0,1,1,2,1,1,2,1,0,0,0,1,0,2,2,1,2,1,2,1,2,1,2,0,0,2,1,2,0 %N A309866 Coefficients of 3-adic expansion of exp(-3). %H A309866 Wikipedia, <a href="https://en.wikipedia.org/wiki/P-adic_exponential_function">p-adic exponential</a> %p A309866 op([1,3], padic:-expp(-3,3,100)); # _Robert Israel_, Aug 20 2019 %o A309866 (PARI) N=100; Vecrev(digits(lift(exp(-3+O(3^N))), 3), N) %Y A309866 Cf. A092554 (exp(-3)), A317675. %K A309866 nonn,base %O A309866 0,2 %A A309866 _Seiichi Manyama_, Aug 20 2019